Peroxycarboxylic acid compositions with reduced odor

ABSTRACT

The present invention relates to compositions of peroxycarboxylic acid that have reduced odor compared to conventional peroxycarboxylic acid compositions, methods employing these reduced-odor compositions, and methods of making these compositions. Typically, the reduced-odor compositions include an amine oxide surfactant.

FIELD OF THE INVENTION

The present invention relates to compositions of peroxycarboxylic acidthat have reduced odor compared to conventional peroxycarboxylic acidcompositions, methods employing these reduced-odor compositions, andmethods of making these compositions. Typically, the reduced-odorcompositions include an amine oxide surfactant.

BACKGROUND OF THE INVENTION

Peroxycarboxylic acid compositions exhibit useful antimicrobialactivity. Many existing compositions including peroxycarboxylic acidssuffer from unacceptable odor.

SUMMARY OF THE INVENTION

The present invention relates to compositions of peroxycarboxylic acidthat have reduced odor compared to conventional peroxycarboxylic acidcompositions, methods employing these reduced-odor compositions, andmethods of making these compositions. Typically, the reduced-odorcompositions include an amine oxide surfactant.

The present invention includes a composition including aperoxycarboxylic acid and an amine oxide surfactant. The composition canbe in the form of a concentrate or a dilute use composition. Theconcentrate composition can include 0.1 to 40 wt-% amine oxide and 0.1to 40 wt-% peroxycarboxylic acid, with a mole ratio of amine oxide toperoxycarboxylic acid of 1 or more. The composition of the invention hasreduced odor of peroxycarboxylic acid compared to a composition lackingthe amine oxide. The composition can also include other components, suchas one or more carboxylic acids, one or more surfactants, one or morehydrotropes, one or more coupling agents, one or more solubilizers, oneor more chelating agents, or the like.

The concentrate composition can be diluted in a major proportion of anaqueous fluid to form an antimicrobial use composition. A usecomposition can include peroxycarboxylic acid at 10 to 10,000 ppm andamine oxide of 10 to 10,000 ppm, with a mole ratio of amine oxide toperoxycarboxylic acid of 1 or more. The composition of the invention hasreduced odor of peroxycarboxylic acid compared to a composition lackingthe amine oxide. The use composition can also include other components,such as one or more carboxylic acids, one or more surfactants, one ormore hydrotropes, one or more coupling agents, one or more solubilizers,one or more chelating agents, or the like.

In another embodiment, the invention includes a method employing thereduced-odor composition of the invention to reduce a population of oneor more microorganisms on an object, such as on a surface or in a fluid.In an embodiment, the invention includes a method employing thereduced-odor composition of the invention to reduce the population of amicroorganism on skin or to treat a disease of skin. In an embodiment,the invention includes a method employing the reduced-odor compositionof the invention to reduce an odor of an object, such as of a surface orof a fluid. In an embodiment, the invention includes a method employingthe reduced-odor composition of the invention to bleach an object. Thesemethods include contacting the object with a reduced-odorperoxycarboxylic acid composition of the invention. Contacting caninclude spraying the composition, immersing the object in thecomposition, foam or gel treating the object with the composition, or acombination thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to antimicrobial compositions including aneffective antimicrobial amount of an amine oxide and peroxycarboxylicacid, with a mole ratio of amine oxide to peroxycarboxylic acid of 1 ormore. The composition of the invention has reduced odor ofperoxycarboxylic acid compared to a composition lacking the amine oxide.The present reduced-odor antimicrobial composition can be usedeffectively to reduce the microbial population of hard surfaces such asthose in facilities and equipment used in the food and beverageindustries. Additionally, the present composition can be used toeffectively reduce the microbial population of food, of dishware, and totreat water.

Definitions

As used herein, the term “microorganisms” refers to any noncellular orunicellular (including colonial) organism. Microorganisms include allprokaryotes. Microorganisms include bacteria (including cyanobacteria),lichens, microfungi, protozoa, virinos, viroids, viruses, and somealgae. As used herein, the term “microbe” is synonymous withmicroorganism.

As used herein, the term “object” refers to a something material thatcan be perceived by the senses, directly and/or indirectly. Objectsinclude a surface, including a hard surface (such as glass, ceramics,metal, natural and synthetic rock, wood, and polymeric), an elastomer orplastic, woven and non-woven substrates, a food processing surface, ahealth care surface, and the like. Objects also include a food product(and its surfaces); a body or stream of water or a gas (e.g., an airstream); and surfaces and articles employed in hospitality andindustrial sectors.

As used herein, the phrase “food product” includes any food substancethat might require treatment with an antimicrobial agent or compositionand that is edible with or without further preparation. Food productsinclude meat (e.g. red meat and pork), seafood, poultry, fruits andvegetables, eggs, living eggs, egg products, ready to eat food, wheat,seeds, roots, tubers, leafs, stems, corms, flowers, sprouts, seasonings,or a combination thereof. The term “produce” refers to food productssuch as fruits and vegetables and plants or plant-derived materials thatare typically sold uncooked and, often, unpackaged, and that cansometimes be eaten raw.

As used herein, the phrase “plant product” includes any plant substanceor plant-derived substance that might require treatment with anantimicrobial agent or composition. Plant products include seeds, nuts,nut meats, cut flowers, plants or crops grown or stored in a greenhouse,house plants, and the like. Plant products include many animal feeds.

As used herein, a processed fruit or vegetable refers to a fruit orvegetable that has been cut, chopped, sliced, peeled, ground, milled,irradiated, frozen, cooked (e.g., blanched, pasteurized), orhomogenized. As used herein a fruit or vegetable that has been washed,colored, waxed, hydro-cooled, refrigerated, shelled, or had leaves,stems or husks removed is not processed.

As used herein, the phrase “meat product” refers to all forms of animalflesh, including the carcass, muscle, fat, organs, skin, bones and bodyfluids and like components that form the animal. Animal flesh includesthe flesh of mammals, birds, fishes, reptiles, amphibians, snails,clams, crustaceans, other edible species such as lobster, crab, etc., orother forms of seafood. The forms of animal flesh include, for example,the whole or part of animal flesh, alone or in combination with otheringredients. Typical forms include, for example, processed meats such ascured meats, sectioned and formed products, minced products, finelychopped products, ground meat and products including ground meat, wholeproducts, and the like.

As used herein, the term “poultry” refers to all forms of any bird kept,harvested, or domesticated for meat or eggs, and including chicken,turkey, ostrich, game hen, squab, guinea fowl, pheasant, quail, duck,goose, emu, or the like and the eggs of these birds. Poultry includeswhole, sectioned, processed, cooked or raw poultry, and encompasses allforms of poultry flesh, by-products, and side products. The flesh ofpoultry includes muscle, fat, organs, skin, bones and body fluids andlike components that form the animal. Forms of animal flesh include, forexample, the whole or part of animal flesh, alone or in combination withother ingredients. Typical forms include, for example, processed poultrymeat, such as cured poultry meat, sectioned and formed products, mincedproducts, finely chopped products and whole products.

As used herein, the phrase “food processing surface” refers to a surfaceof a tool, a machine, equipment, a structure, a building, or the likethat is employed as part of a food processing, preparation, or storageactivity. Examples of food processing surfaces include surfaces of foodprocessing or preparation equipment (e.g., slicing, canning, ortransport equipment, including flumes), of food processing wares (e.g.,utensils, dishware, wash ware, and bar glasses), and of floors, walls,or fixtures of structures in which food processing occurs. Foodprocessing surfaces are found and employed in food anti-spoilage aircirculation systems, aseptic packaging sanitizing, food refrigerationand cooler cleaners and sanitizers, ware washing sanitizing, blanchercleaning and sanitizing, food packaging materials, cutting boardadditives, third-sink sanitizing, beverage chillers and warmers, meatchilling or scalding waters, sanitizing gels, cooling towers, foodprocessing antimicrobial garment sprays, and non-to-low-aqueous foodpreparation lubricants, oils, and rinse additives.

As used herein, the phrase “air streams” includes food anti-spoilage aircirculation systems. Air streams also include air streams typicallyencountered in hospital, surgical, infirmity, birthing, mortuary, andclinical diagnosis rooms.

As used herein, the term “waters” includes food process or transportwaters. Food process or transport waters include produce transportwaters (e.g., as found in flumes, pipe transports, cutters, slicers,blanchers, retort systems, washers, and the like), belt sprays for foodtransport lines, boot and hand-wash dip-pans, third-sink rinse waters,and the like. Waters also include domestic and recreational waters suchas pools, spas, recreational flumes and water slides, fountains, and thelike.

As used herein, the phrase “health care surface” refers to a surface ofan instrument, a device, a cart, a cage, furniture, a structure, abuilding, or the like that is employed as part of a health careactivity. Examples of health care surfaces include surfaces of medicalor dental instruments, of medical or dental devices, of electronicapparatus employed for monitoring patient health, and of floors, walls,or fixtures of structures in which health care occurs. Health caresurfaces are found in hospital, surgical, infirmity, birthing, mortuary,and clinical diagnosis rooms. These surfaces can be those typified as“hard surfaces” (such as walls, floors, bed-pans, etc.,), or woven andnon-woven surfaces (such as surgical garments, draperies, bed linens,bandages, etc.,), or patient-care equipment (such as respirators,diagnostic equipment, shunts, body scopes, wheel chairs, beds, etc.,),or surgical and diagnostic equipment. Health care surfaces includearticles and surfaces employed in animal health care.

As used herein, the term “instrument” refers to the various medical ordental instruments or devices that can benefit from cleaning with areduced-odor composition according to the present invention.

As used herein, the phrases “medical instrument”, “dental instrument”,“medical device”, “dental device”, “medical equipment”, or “dentalequipment” refer to instruments, devices, tools, appliances, apparatus,and equipment used in medicine or dentistry. Such instruments, devices,and equipment can be cold sterilized, soaked or washed and then heatsterilized, or otherwise benefit from cleaning in a composition of thepresent invention. These various instruments, devices and equipmentinclude, but are not limited to: diagnostic instruments, trays, pans,holders, racks, forceps, scissors, shears, saws (e.g. bone saws andtheir blades), hemostats, knives, chisels, rongeurs, files, nippers,drills, drill bits, rasps, burrs, spreaders, breakers, elevators,clamps, needle holders, carriers, clips, hooks, gouges, curettes,retractors, straightener, punches, extractors, scoops, keratomes,spatulas, expressors, trocars, dilators, cages, glassware, tubing,catheters, cannulas, plugs, stents, arthoscopes and related equipment,and the like, or combinations thereof.

As used herein, “agricultural” or “veterinary” objects or surfacesinclude animal feeds, animal watering stations and enclosures, animalquarters, animal veterinarian clinics (e.g. surgical or treatmentareas), animal surgical areas, and the like.

As used herein, weight percent (wt-%), percent by weight, % by weight,and the like are synonyms that refer to the concentration of a substanceas the weight of that substance divided by the weight of the compositionand multiplied by 100.

As used herein, the terms “mixed” or “mixture” when used relating to“peroxycarboxylic acid composition” or “peroxycarboxylic acids” refer toa composition or mixture including more than one peroxycarboxylic acid,such as a composition or mixture including peroxyacetic acid andperoxyoctanoic acid.

As used herein, the term “about” modifying the quantity of an ingredientin the compositions of the invention or employed in the methods of theinvention refers to variation in the numerical quantity that can occur,for example, through typical measuring and liquid handling proceduresused for making concentrates or use solutions in the real world; throughinadvertent error in these procedures; through differences in themanufacture, source, or purity of the ingredients employed to make thecompositions or carry out the methods; and the like. The term about alsoencompasses amounts that differ due to different equilibrium conditionsfor a composition resulting from a particular initial mixture. Whetheror not modified by the term “about”, the claims include equivalents tothe quantities.

Differentiation of antimicrobial “-cidal” or “-static” activity, thedefinitions which describe the degree of efficacy, and the officiallaboratory protocols for measuring this efficacy are considerations forunderstanding the relevance of antimicrobial agents and compositions.Antimicrobial compositions can effect two kinds of microbial celldamage. The first is a lethal, irreversible action resulting in completemicrobial cell destruction or incapacitation. The second type of celldamage is reversible, such that if the organism is rendered free of theagent, it can again multiply. The former is termed bacteriocidal and thelater, bacteriostatic. A sanitizer and a disinfectant are, bydefinition, agents which provide antibacterial or bacteriocidalactivity. In contrast, a preservative is generally described as aninhibitor or bacteriostatic composition.

For the purpose of this patent application, successful reduction ofmicroorganisms is achieved when the populations of microorganisms arereduced by at least about 0.3-1 log₁₀. In this application, such apopulation reduction is the minimum acceptable for the processes. Anyincreased reduction in population of microorganisms is an added benefitthat provides higher levels of protection.

Reduced-Odor Peroxycarboxylic Acid Compositions

The present invention relates to reduced-odor compositions containing aperoxycarboxylic acid. Typically, the reduced-odor compositions alsoinclude an amine oxide at a mole ratio of amine oxide toperoxycarboxylic acid of 1 or more. Typically, the peroxycarboxylic acidis an antimicrobial agent. Many peroxycarboxylic acid compositionexhibit a sharp, annoying, or otherwise unacceptable odor. Surprisingly,such an unacceptable odor can be reduced by adding an amine oxide to theperoxycarboxylic acid. The present composition of the invention hasreduced odor of peroxycarboxylic acid compared to a composition lackingthe amine oxide.

The peroxycarboxylic acid can be made in the presence of the amineoxide, or the amine oxide can be added after forming theperoxycarboxylic acid. In an embodiment, the amine oxide can be employedin food products or for cleaning or sanitizing food processing equipmentor materials. In an embodiment, the amine oxide can be employed in ahealth-care environment. In an embodiment, the amine oxide is non-toxic.In an embodiment, the amine oxide can be employed according toguidelines from government agencies, such as the Food and DrugAdministration, without adverse labeling requirements, such as labelingwith a skull and cross bones or the like. Preferred amine oxides includeoctyl amine oxide (e.g., octyldimethylamine oxide), lauryldimethyl amineoxide, and the like.

The amine oxide is typically present in a quantity that effectivelyreduces odor of the peroxycarboxylic acid. Suitable levels of amineoxide include a mole ratio of amine oxide to peroxycarboxylic acid of 1or more. In an embodiment, the mole ratio is greater than or equal to 2.In an embodiment, the mole ratio is greater than or equal to 3. In anembodiment, the mole ratio is 2 to 5. In an embodiment, the mole ratiois 3 to 5. Octyl dimethyl amine oxide has a molecular weight of about 3(e.g. 2.7) times as great as peroxyacetic acid, and applicable weightratios can be calculated on such a basis.

In an embodiment, the composition includes about 15 to about 60 wt-%amine oxide. In an embodiment, the composition includes about 30 toabout 50 wt-% amine oxide. In an embodiment, the composition includesabout 45 wt-% amine oxide.

Amine Oxides

Examples of suitable amine oxides include those having a general formulaof

wherein R₁, R₂, and R₃ are independently selected from saturated orunsaturated and straight or branched alkyl groups having from 1-24carbons and aromatic groups, etc. and which can optionally contain O, Nor P as a heteroatom or polyalkoxy groups. Examples of amine oxidesinclude, but are not limited to: alkyldimethylamine oxide,dialkylmethylamine oxide, alkyldialkoxyamine oxide, dialkylalkoxyamineoxide, dialkyletheramine oxide and dialkoxyetheramine oxide. In anembodiment, R₁ is an alkyl group having 4-18 carbons and R₂ and R₃ arealkyl groups having 1-18 carbons. In an embodiment, R₁ is an alkyl grouphaving 6-10 carbons and R₂ and R₃ are alkyl groups having 1-2 carbons.In an embodiment, R₁ is an alkyl group having 8 carbons (an octyl group)and R₂ and R₃ are alkyl groups having 1-2 carbons. In an embodiment, R₁is an alkyl group having 12 carbons (a lauryl group) and R₂ and R₃ arealkyl groups having 1-2 carbons.

Preferred amine oxides include octyldimethylamine oxide,myristyldimethylamine oxide, didecylmethylamine oxide, methylmorpholineoxide, tetradecyldiethoxyamine oxide, and lauryldimethylamine oxide.Preferred amine oxides include octyldimethylamine oxide andlauryldimethylamine oxide.

Peroxycarboxylic Acids

Peroxycarboxylic (or percarboxylic) acids generally have the formulaR(CO₃H)_(n), where R is an alkyl, arylalkyl, cycloalkyl, aromatic,heterocyclic, or ester group, such as an alkyl ester group; and n isone, two, or three, and named by prefixing the parent acid with peroxy.Ester groups are defined as R groups including organic moieties (such asthose listed above for R) and ester moieties. Preferred ester groupsinclude aliphatic ester groups, such as R₁OC(O)R₂— where each of R₁ andR₂ can be aliphatic, preferably alkyl, groups described above for R.Preferably R₁ and R₂ are each independently small alkyl groups, such asalkyl groups with 1 to 5 carbon atoms.

While peroxycarboxylic acids are not as stable as carboxylic acids,their stability generally increases with increasing molecular weight.Thermal decomposition of these acids can generally proceed by freeradical and nonradical paths, by photodecomposition or radical-induceddecomposition, or by the action of metal ions or complexes.Percarboxylic acids can be made by the direct, acid catalyzedequilibrium action of hydrogen peroxide with the carboxylic acid, byautoxidation of aldehydes, or from acid chlorides, and hydrides, orcarboxylic anhydrides with hydrogen or sodium peroxide.

Peroxycarboxylic acids useful in the compositions and methods of thepresent invention include peroxyformic, peroxyacetic, peroxypropionic,peroxybutanoic, peroxypentanoic, peroxyhexanoic, peroxyheptanoic,peroxyoctanoic, peroxynonanoic, peroxydecanoic, peroxyundecanoic,peroxydodecanoic, peroxylactic, peroxycitric, peroxymaleic,peroxyascorbic, peroxyhydroxyacetic (peroxyglycolic), peroxyoxalic,peroxymalonic, peroxysuccinic, peroxyglutaric, peroxyadipic,peroxypimelic, peroxysuberic, and peroxysebacic acid, and mixturesthereof. Useful peroxycarboxylic acids also include the esterperoxycarboxylic acids described herein and compositions of the presentinvention including those ester peroxycarboxylic acids.

Peroxy forms of carboxylic acids with more than one carboxylate moietycan have one or more of the carboxyl moieties present as peroxycarboxylmoieties. These peroxycarboxylic acids have been found to provide goodantimicrobial action with good stability in aqueous mixtures. In apreferred embodiment, the composition of the invention utilizes acombination of several different peroxycarboxylic acids.

In a preferred embodiment, the composition of the invention utilizes acombination of several different peroxycarboxylic acids. Preferably, thecomposition includes one or more small C₂-C₄ peroxycarboxylic acids, oneor more large C₈-C₁₂ peroxycarboxylic acids, and/or one or more alkylester peroxycarboxylic acid compositions. Especially preferred is anembodiment in which the small peroxycarboxylic acid is peroxyacetic acidand the large acid is either peroxyoctanoic acid or peroxydecanoic acid.

Ester Peroxycarboxylic Acids

As used herein, ester peroxycarboxylic acid refers to a molecule havingthe formula:

In this formula, R₁ and R₂ can independently be any of a wide variety oforganic groups (e.g. alkyl, linear or cyclic, aromatic or saturated) orsubstituted organic groups (e.g., with one or more heteroatoms ororganic groups). Ester peroxycarboxylic acid can be made using methodstypically employed for producing peroxycarboxylic acid, such asincubating the corresponding ester carboxylic acid with hydrogenperoxide.

Preferred ester peroxycarboxylic acids include alkyl esterperoxycarboxylic acids, preferably having the formula:

where R represents an alkyl group having from 1 to 4 carbons and x is 0to 5, preferably 1 to 4. The alkyl group can be either straight chain orbranched. Preferably, R is a methyl, ethyl, propyl, or isobutyl group.Preferably, x is 2, 3, or 4.

In one preferred embodiment, the composition of the present inventionincludes a mixture of alkyl ester peroxycarboxylic acids in which x is2, 3, and 4. Such a mixture includes monoesters of peroxyadipic,peroxyglutaric, and peroxysuccinic acids. In another preferredembodiment, a majority of the ester peroxycarboxylic acid in thecomposition has x equal to 3. In a preferred embodiment, R is a C₁-C₄alkyl. In a preferred embodiment, x is 1, 2, 3, or 4. Most preferably, Ris a C₁ alkyl, C₃ alkyl, or C₄ alkyl, and x is 2, 3 or 4.

In another preferred embodiment, R represents an alkyl group having from1 to 8 carbons, and x is 0 to 10. The alkyl group can be either straightchain or branched, preferably straight chain. In this embodiment,preferably x is 4-8 and R is C₁ to C₄ alkyl, preferably methyl or ethyl.

Alkyl ester peroxycarboxylic acids useful in this invention includemonomethyl monoperoxyoxalie acid, monomethyl monoperoxymalonic acid,monomethyl monoperoxysuccinic acid, monomethyl monoperoxyglutaric acid,monomethyl monoperoxyadipic acid, monomethyl monoperoxypimelic acid,monomethyl monoperoxysuberic acid, and monomethyl monoperoxysebacicacid; monoethyl monoperoxyoxalic acid, monoethyl monoperoxymalonic acid,monoethyl monoperoxysuccinic acid, monoethyl monoperoxyglutaric acid,monoethyl monoperoxyadipic acid, monoethyl monoperoxypimelic acid,monoethyl monoperoxysuberic acid, and monoethyl monoperoxysebacic acid;monopropyl monoperoxyoxalic acid, monopropyl monoperoxymalonic acid,monopropyl monoperoxysuccinic acid, monopropyl monoperoxyglutaric acid,monopropyl monoperoxyadipic acid, monopropyl monoperoxypimelic acid,monopropyl monoperoxysuberic acid, and monopropyl monoperoxysebacicacid, in which propyl can be n- or isopropyl; and monobutylmonoperoxyoxalic acid, monobutyl monoperoxymalonic acid, monobutylmonoperoxysuccinic acid, monobutyl monoperoxyglutaric acid, monobutylmonoperoxyadipic acid, monobutyl monoperoxypimelic acid, monobutylmonoperoxysuberic acid, and monobutyl monoperoxysebacic acid, in whichbutyl can be n-, iso-, or t-butyl.

In a preferred embodiment, the antimicrobial composition includes one ormore alkyl ester peroxycarboxylic acids and a peroxycarboxylic acidhaving from 2 to 12 carbon atoms. Preferably, such an antimicrobialcomposition includes peroxyacetic acid, or peroxyoctanoic acid, orperoxydecanoic acid, and monomethyl monoperoxyoxalic acid, monomethylmonoperoxymalonic acid, monomethyl monoperoxysuccinic acid, monomethylmonoperoxyglutaric acid, monomethyl monoperoxyadipic acid, monomethylmonoperoxypimelic acid, monomethyl monoperoxysuberic acid, or monomethylmonoperoxysebacic acid; monoethyl monoperoxyoxalic acid, monoethylmonoperoxymalonic acid, monoethyl monoperoxysuccinic acid, monoethylmonoperoxyglutaric acid, monoethyl monoperoxyadipic acid, monoethylmonoperoxypimelic acid, monoethyl monoperoxysuberic acid, or monoethylmonoperoxysebacic acid; monopropyl monoperoxyoxalic acid, monopropylmonoperoxymalonic acid, monopropyl monoperoxysuccinic acid, monopropylmonoperoxyglutaric acid, monopropyl monoperoxyadipic acid, monopropylmonoperoxypimelic acid, monopropyl monoperoxysuberic acid, or monopropylmonoperoxysebacic acid, in which propyl can be n- or isopropyl; ormonobutyl monoperoxyoxalic acid, monobutyl monoperoxymalonic acid,monobutyl monoperoxysuccinic acid, monobutyl monoperoxyglutaric acid,monobutyl monoperoxyadipic acid, monobutyl monoperoxypimelic acid,monobutyl monoperoxysuberic acid, or monobutyl monoperoxysebacic acid,in which butyl can be n-, iso-, or t-butyl, or mixtures thereof.Preferably, in such mixtures the alkyl ester peroxycarboxylic acid isone of the above, and the peroxycarboxylic acid having from 2 to 12carbon atoms is peroxyacetic acid or peroxyoctanoic acid; combined in aratio of about 1 to about 10 parts by weight of peroxyacetic acid pereach 1 part of carboxylic acid. In another embodiment, when a blendedacid is used, the peroxycarboxylic acids are blended in proportions thatrange from about 1 part to about 20 parts by weight of alkyl esterperoxyacid to mono- or di-peroxycarboxylic acid having up to 12 carbonatoms. In another preferred embodiment, the combination ofperoxycarboxylic acid includes an alkyl ester peroxyacid and a mono- ordi-peroxycarboxylic acid having up to 12 carbon atoms.

The amount of alkyl ester peroxycarboxylic acid in use and concentratecompositions can range up to the limits at which the peroxycarboxylicacid can be dissolved or suspended in the composition. Preferably, thealkyl ester peroxycarboxylic acid is present in a use or concentratecomposition at a concentration of from about 0.0001 to about 20% byweight, preferably from about 0.05 to about 15% by weight, and morepreferably from about 4 to about 10% by weight. Typically usecompositions include at least 0.1%, preferably at least 1%, by weightalkyl ester peroxycarboxylic acid.

Reduced-odor compositions of ester peroxycarboxylic acid can alsoinclude other ingredients, for example, to increase solubility of theester peroxycarboxylic acid or to maintain the pH of the composition.Preferably the reduced-odor composition includes a surfactant. It isbelieved that the surfactant can increase the solubility of the esterperoxycarboxylic acid. Suitable surfactants include nonionicsurfactants, anionic surfactants, cationic surfactants, amphotericsurfactants, and the like. Preferred surfactants include alkylbenzenesulfonic acids and their salts, alkyl sulfonates, straight-chain orbranched alcohol ethoxylates, amine oxides, and the like. Preferably thesurfactant is present at about 0 to about 15 wt-% of the composition,preferably about 0 to about 10 wt-%, and most preferably about 0 toabout 8 wt-%.

Preferably the reduced-odor composition includes a buffer. Preferredbuffers maintain the pH of the composition, after dilution to the useconcentration, below about 7, preferably below about 5, and morepreferably below about 4. Preferred buffers include citric acid and itssalts, phosphoric acid and its salts, succinic acid and its salts,adipic acid and its salts, glutaric acid and its salts, acetic acid andits salts, boric acid and its salts, and mixtures thereof. Preferablythe buffer is present at about 0 to about 20 wt-% of the composition,preferably about 0 to about 10 wt-%, and most preferably about 0 toabout 7 wt-%

The reduced-odor compositions of the invention can be formulated as aliquid, a gel, an aerosol, a gas, a wax, a solid, or a powder, or as asolution or suspension containing such a composition.

Compositions of Peroxycarboxylic Acids

A preferred antimicrobial reduced-odor peroxycarboxylic acid compositionof the present invention is effective for killing one or more of thefood-borne pathogenic bacteria associated with a food product, such asSalmonella typhimurium, Salmonella javiana, Campylobacter jejuni,Listeria monocytogenes, and Escherichia coli O157:H7, yeast, mold andthe like. The compositions and methods of the present invention haveactivity against a wide variety of microorganisms such as Gram positive(for example, Listeria monocytogenes) and Gram negative (for example,Escherichia coli) bacteria, yeast, molds, bacterial spores, viruses,etc. The compositions and methods of the present invention, as describedabove, have activity against a wide variety of human pathogens. Thecompositions and methods can kill a wide variety of microorganisms on afood processing surface, on the surface of a food product, or in waterused for washing or processing of food product.

A preferred antimicrobial reduced-odor peroxycarboxylic acid compositionof the present invention is effective for killing one or more of thepathogenic bacteria associated with a health care surfaces andenvironments, such as Salmonella typhimurium, Staphylococcus aureus,Salmonella choleraesurus, Pseudomonas aeruginosa, and Escherichia coli,mycobacteria, yeast, mold, and the like. The compositions and methods ofthe present invention have activity against a wide variety ofmicroorganisms such as Gram positive (for example, Staphylococcusaureus) and Gram negative (for example, Pseudomonas aeruginosa)bacteria, yeast, molds, bacterial spores, viruses, etc. The compositionsand methods of the present invention, as described above, have activityagainst a wide variety of human pathogens. The compositions and methodscan kill a wide variety of microorganisms on a health care surface or ina health care environment.

The preferred compositions include concentrate compositions and usecompositions. Typically, an antimicrobial concentrate composition can bediluted, for example with water, to form an antimicrobial usecomposition. In a preferred embodiment, the concentrate composition isdiluted into water employed for washing or processing food product.

The advantageous stability of mixed peroxycarboxylic acid compositionsin such methods, which include the presence of food product or healthcare debris or residue, makes these compositions competitive withcheaper, less stable, and potentially toxic chlorinated compounds.Preferred methods of the present invention include agitation orsonication of the use composition, particularly as a concentrate isadded to water to make the use composition. Preferred methods includewater systems that have some agitation, spraying, or other mixing of thesolution.

The level of reactive species, such as peroxy acids and/or hydrogenperoxide, in a use composition can be affected, typically diminished, byorganic matter that is found in or added to the use composition. Forexample, when the use composition is a bath or spray used for washingfood product, food product organic matter or accompanying organic matterwill consume peroxy acid and peroxide. Thus, the amounts of ingredientslisted for the use compositions refer to the composition before or earlyin use, with the understanding that the amounts will diminish as organicmatter is added to the use composition.

In addition, the concentrate and use compositions change with age. It isbelieved that in approximately one year at ambient conditions the amountof peroxycarboxylic acid in the compositions can decrease to about 50%to about 80%, preferably about 80% to about 85%, of the initialequilibrium values or use composition levels. Such aged compositions areincluded in the scope of the present invention.

In an embodiment, the compositions of the present invention preferablyinclude only ingredients that can be employed in food products or infood product washing, handling, or processing, for example, according togovernment (e.g., FDA or USDA) rules and regulations. Preferably, thecomposition is free of any non-ester peroxycarboxylic acid or carboxylicacid with 10, 12, or more carbon atoms. Such non-ester 10, 12, or morecarbon acids can impart undesirable residues (e.g., bad tasting and/ormalodorous) to food product.

Each of the compositions listed above can be formulated by combiningeach of the listed ingredients. In addition, certain compositionsincluding both acid and peroxy acid can be formulated by combining theacids and hydrogen peroxide, which forms peroxy acids. Typically, the pHof an equilibrium mixture is less than about 1 or about 2, and the pH ofa 1% solution of the equilibrium mixture in water is about 2 to about 7,depending on the other components of the 1% solution, and the pH of ause composition can be from about 3 to about 7 depending on the othercomponents.

Among other constituents, the composition of the present invention caninclude a carboxylic acid. Generally, carboxylic acids have the formulaR-COOH wherein the R can represent any number of different groupsincluding aliphatic groups, alicyclic groups, aromatic groups,heterocyclic groups, and ester groups, such as alkyl ester groups, allof which can be saturated or unsaturated and/or substituted orunsubstituted. Carboxylic acids can have one, two, three, or morecarboxyl groups. Preferred ester groups include aliphatic ester groups,such as R₁OC(O)R₂— where each of R₁ and R₂ can be aliphatic, preferablyalkyl, groups described above for R. Preferably R₁ and R₂ are eachindependently small alkyl groups, such as alkyl groups with 1 to 4carbon atoms.

The composition and methods of the invention can employ carboxylic acidscontaining as many as 18 carbon atoms. Examples of suitable carboxylicacids include formic, acetic, propionic, butanoic, pentanoic, hexanoic,heptanoic, octanoic, nonanoic, decanoic, undecanoic, dodecanoic, lactic,maleic, ascorbic, citric, hydroxyacetic (glycolic), neopentanoic,neoheptanoic, neodecanoic, oxalic, malonic, succinic, glutaric, adipic,pimelic suberic, and sebacic acid. Examples of suitable alkyl estercarboxylic acids include monomethyl oxalic acid, monomethyl malonicacid, monomethyl succinic acid, monomethyl glutaric acid, monomethyladipic acid, monomethyl pimelic acid, monomethyl suberic acid, andmonomethyl sebacic acid; monoethyl oxalic acid, monoethyl malonic acid,monoethyl succinic acid, monoethyl glutaric acid, monoethyl adipic acid,monoethyl pimelic acid, monoethyl suberic acid, and monoethyl sebacicacid; monopropyl oxalic acid, monopropyl malonic acid, monopropylsuccinic acid, monopropyl glutaric acid, monopropyl adipic acid,monopropyl pimelic acid, monopropyl suberic acid, and monopropyl sebacicacid, in which propyl can be n- or isopropyl; and monobutyl oxalic acid,monobutyl malonic acid, monobutyl succinic acid, monobutyl glutaricacid, monobutyl adipic acid, monobutyl pimelic acid, monobutyl subericacid, and monobutyl sebacic acid, in which butyl can be n-, iso-, ort-butyl.

Carboxylic acids which are generally useful are those having one or twocarboxyl groups where the R group is a primary alkyl chain having alength of C₂ to C₂. The primary alkyl chain is that carbon chain of themolecule having the greatest length of carbon atoms and directlyappending carboxyl functional groups. Longer chain carboxylic acidanalogs, including hexanoic, heptanoic, octanoic, nonanoic, anddecanoic, can reduce surface tension to assist in wetting of hydrophobicsurfaces like skin.

In a preferred embodiment, the antimicrobial composition includes one ormore mono- or di-carboxylic acids having up to 18 carbon atoms.Preferred mono- or di-carboxylic acids having up to 18 carbon atomsinclude acetic acid, lactic acid, glycolic acid, citric acid, heptanoicacid, octanoic acid, nonanoic acid, or a mixture thereof. In anotherpreferred embodiment, the antimicrobial composition includes analpha-hydroxy mono- or di-carboxylic acid having from 3 to 6 carbonatoms, preferably lactic acid.

Carboxylic acids that are generally useful include ester carboxylicacids, such as alkyl ester carboxylic acids. Preferred alkyl estercarboxylic acids include those with the formula:

where R represents an alkyl group having from 1 to 4 carbons and x is 0to 5, preferably 1 to 4. The alkyl group can be either straight chain orbranched. Preferably, R is a methyl, ethyl, propyl, or isobutyl group.Preferably, x is 2, 3, or 4.

In one preferred embodiment, the composition of the present inventionincludes a mixture of alkyl ester peroxycarboxylic acids in which x is2, 3, and 4. Such a mixture includes monoesters of peroxyadipic,peroxyglutaric, and peroxysuccinic acids. In another preferredembodiment, a majority of the ester peroxycarboxylic acid in thecomposition has x equal to 3. In a preferred embodiment, R is a C₁-C₄alkyl. In a preferred embodiment, x is 1, 2, 3, or 4. Most preferably, Ris a C₁ alkyl, C₃ alkyl, or C₄ alkyl, and x is 2, 3 or 4.

In another preferred embodiment, R represents an alkyl group having from1 to 8 carbons, and x is 0 to 10. The alkyl group can be either straightchain or branched, preferably straight chain. In this embodiment,preferably x is 4-8 and R is C₁ to C₄ alkyl, preferably methyl or ethyl.

Generally, the concentration of carboxylic acid within the compositionused in the process of the invention ranges from about 0.5 wt-% to about80 wt-%, preferably from about 5 wt-% to about 50 wt-%, and mostpreferably from about 10 wt-% to about 30 wt-%. Typically theconcentration of ester carboxylic acid ranges up to about 15% by weight,although concentrations of up to 50% can be employed in certainembodiments, preferably from about 0.05 to about 15%, and mostpreferably from about 1% to about 9%.

Hydrogen Peroxide

The reduced-odor compositions of the invention typically also include ahydrogen peroxide constituent. Hydrogen peroxide in combination with thepercarboxylic acid provides certain antimicrobial action againstmicroorganisms. Additionally, hydrogen peroxide can provide aneffervescent action which can irrigate any surface to which it isapplied. Hydrogen peroxide works with a mechanical flushing action onceapplied which further cleans the surface. An additional advantage ofhydrogen peroxide is the food compatibility of this composition upon useand decomposition. For example, combinations of peroxyacetic acid,peroxyoctanoic acid, and hydrogen peroxide result in acetic acid,octanoic acid, water, and oxygen upon decomposition, all of which arefood product compatible.

Many oxidizing agents can be used for generating peroxycarboxylic acids.Suitable oxidizing agents, in addition to hydrogen peroxide, includesalts of perborate, percarbonate, and persulfate. Hydrogen peroxide isgenerally preferred for several reasons. After application of theH₂O₂/peroxycarboxylic acid germicidal agent, the residue left merelyincludes water and an acidic constituent. Deposition of these productson the surface of a food product processing apparatus, such as a bath orspray apparatus, will not adversely effect the apparatus, the handlingor processing, or the food product washed therein.

Hydrogen peroxide (H₂O₂), has a molecular weight of 34.014 and it is aweakly acidic, clear, colorless liquid. The four atoms are covalentlybonded in a H—O—O—H structure. Generally, hydrogen peroxide has amelting point of −0.41° C., a boiling point of 150.2° C., a density at25° C. of 1.4425 grams per cm³, and a viscosity of 1.245 centipoise at20° C.

Carrier

The reduced-odor composition of or employed in the method of theinvention also includes a carrier. The carrier provides a medium whichdissolves, suspends, or carries the other components of the reduced-odorcomposition. For example, the carrier can provide a medium forsolubilization and production of peroxycarboxylic acid and for formingan equilibrium mixture. The carrier also functions to deliver and wetthe reduced-odor composition of the invention to the food product. Tothis end, the carrier may contain any component or components that canfacilitate these functions.

Polyols are also useful carriers, including polypropylene glycols,polyethylene glycols, sorbitol, and the like. Any of these compounds maybe used singly or in combination with other organic or inorganicconstituents or, in combination with water or in mixtures thereof.

Generally, the carrier makes up a large portion of the composition andmay be the balance of the composition apart from the activeantimicrobial components, adjuvants, and the like. Here again, thecarrier concentration and type will depend upon the nature of thecomposition as a whole, the environmental storage, and method ofapplication including concentration of the antimicrobial agent, amongother factors. Notably the carrier should be chosen and used at aconcentration which does not inhibit the antimicrobial efficacy of theactive agent in the composition.

Adjuvants

The reduced-odor composition of or employed in the method of theinvention can also include any number of adjuvants. Specifically, thecomposition can include stabilizing agents, wetting agents, hydrotropes,thickeners, a surfactant, foaming agents, acidifiers, as well aspigments or dyes among any number of constituents which can be added tothe composition. Such adjuvants can be preformulated with thereduced-odor composition or added to the system simultaneously, or evenafter, the addition of the reduced-odor composition. The composition canalso contain any number of other constituents as necessitated by theapplication, which are known to those of skill in the art and which canfacilitate the activity of the present invention.

Stabilizing Agents

Stabilizing agents can be added to the composition, for example, tostabilize the peracid and hydrogen peroxide and prevent the prematureoxidation of this constituent within the composition.

Chelating agents or sequestrants generally useful as stabilizing agentsin the present compositions include alkyl diamine polyacetic acid-typechelating agents such as EDTA (ethylene diamine tetraacetate tetrasodiumsalt), acrylic and polyacrylic acid-type stabilizing agents, phosphonicacid, and phosphonate-type chelating agents among others. Preferablesequestrants include phosphonic acids and phosphonate salts including1-hydroxy ethylidene-1,1-diphosphonic acid (CH₃C(PO₃H₂)₂OH) (HEDP),amino[tri(methylene phosphonic acid)] ([CH₂PO₃H₂]₂(ethylenediamine[tetra methylene-phosphonic acid)], 2-phosphenebutane-1,2,4-tricarboxylic acid, as well as the alkyl metal salts,ammonium salts, or alkyloyl amine salts, such as mono, di, ortetra-ethanolamine salts. The stabilizing agent is used in aconcentration ranging from about 0 weight percent to about 20 weightpercent of the composition, preferably from about 0.1 weight percent toabout 10 weight percent of the composition, and most preferably fromabout 0.2 weight percent to 5 weight percent of the composition.

Amino phosphates and phosphonates are also suitable for use as chelatingagents in the compositions and include ethylene diamine (tetramethylenephosphonates), nitrilotrismethylene phosphates, diethylenetriamine(pentamethylene phosphonates). These amino phosphonates commonly containalkyl or alkaline groups with less than 8 carbon atoms. The phosphonicacid may also include a low molecular weight phosphonopolycarboxylicacid such as one having about 2-4 carboxylic acid moieties and about 1-3phosphonic acid groups. Such acids include 1-phosphono-1-methylsuccinicacid, phosphonosuccinic acid and 2-phosphonobutane-1,2,4-tricarboxylicacid.

Commercially available food additive chelating agents includephosphonates sold under the trade name DEQUEST® including, for example,1-hydroxyethylidene-1,1-diphosphonic acid, available from MonsantoIndustrial Chemicals Co., St. Louis, Mo., as DEQUEST® 2010;amino(tri(methylenephosphonic acid)), (N[CH₂PO₃H₂]₃), available fromMonsanto as DEQUEST® 2000; ethylenediamine[tetra(methylenephosphonicacid)] available from Monsanto as DEQUEST® 2041; and2-phosphonobutane-1,2,4-tricarboxylic acid available from Mobay ChemicalCorporation, Inorganic Chemicals Division, Pittsburgh, Pa., as BayhibitAM.

The above-mentioned phosphonic acids can also be used in the form ofwater soluble acid salts, particularly the alkali metal salts, such assodium or potassium; the ammonium salts or the alkylol amine salts wherethe alkylol has 2 to 3 carbon atoms, such as mono-, di-, ortriethanolamine salts. If desired, mixtures of the individual phosphonicacids or their acid salts can also be used.

The concentration of chelating agent useful in the present inventiongenerally ranges from about 0.01 to about 10 wt-%, preferably from about0.1 to about 5 wt-%, most preferably from about 0.5 to about 2 wt-%.

Wetting or Defoaming Agents

Also useful in the composition are wetting and defoaming agents. Wettingagents function to increase the surface contact or penetration activityof the reduced-odor composition. Wetting agents which can be used in thecomposition include any of those constituents known within the art toraise the surface activity of the composition.

Along these lines, surfactants, and especially nonionic surfactants, canalso be useful in the present invention. Nonionic surfactants which canbe useful in the present invention are those which include ethyleneoxide moieties, propylene oxide moieties, as well mixtures thereof, andethylene oxide-propylene oxide moieties in either heteric or blockformation. Additionally useful in the present invention are nonionicsurfactants which include an alkyl ethylene oxide compounds, alkylpropylene oxide compounds, as well as mixtures thereof, and alkylethylene oxide-propylene oxide compounds where the ethylene oxidepropylene oxide moiety is either in heteric or block formation. Furtheruseful in the present invention are nonionic surfactants having anymixture or combination of ethylene oxide-propylene oxide moieties linkedto a alkyl chain where the ethylene oxide and propylene oxide moietiescan be in any randomized or ordered pattern and of any specific length.Nonionic surfactants useful in the present invention can also includerandomized sections of block and heteric ethylene oxide propylene oxide,or ethylene oxide-propylene oxide, such as ethylene diamine ethyleneoxides, ethylene diamine propylene oxides, mixtures thereof, andethylene diamine EO-PO compounds, including those sold under thetradename Tetronic.

Generally, the concentration of nonionic surfactant used in acomposition of the present invention can range from about 0 wt-% toabout 5 wt-% of the composition, preferably from about 0 wt-% to about 2wt-% of the concentrate composition, and most preferably from about 0wt-% to about 1 wt-% of the composition.

The composition can also contain additional ingredients as necessary toassist in defoaming. Generally, defoamers which can be used inaccordance with the invention include silica and silicones; aliphaticacids or esters; alcohols; sulfates or sulfonates; amines or amides;halogenated compounds such as fluorochlorohydrocarbons; vegetable oils,waxes, mineral oils as well as their sulfated derivatives; fatty acidsoaps such as alkali, alkaline earth metal soaps; and phosphates andphosphate esters such as alkyl and alkaline diphosphates, and tributylphosphates among others; and mixtures thereof.

Especially preferably, are those antifoaming agents or defoamers whichare of food grade quality given the application of the method of theinvention. To this end, one of the more effective antifoaming agentsincludes silicones. Silicones such as dimethyl silicone, glycolpolysiloxane, methylphenol polysiloxane, trialkyl or tetralkyl silanes,hydrophobic silica defoamers and mixtures thereof can all be used indefoaming applications. Commercial defoamers commonly available includesilicones such as Ardefoam® from Armour Industrial Chemical Companywhich is a silicone bound in an organic emulsion; Foam Kill® or Kresseo®available from Krusable Chemical Company which are silicone andnon-silicone type defoamers as well as silicone esters; and Anti-Foam A®and DC-200 from Dow Corning Corporation which are both food grade typesilicones among others. These defoamers can be present at aconcentration range from about 0.01 wt-% to 5 wt-%, preferably fromabout 0.01 wt-% to 2 wt-%, and most preferably from about 0.01 wt-% toabout 1 wt-%.

Hydrotrope

The food product wash composition of the invention or employed in themethod of the invention can also include a hydrotrope coupler orsolubilizer. Such materials can be used to ensure that the compositionremains phase stable and in a single highly active aqueous form. Suchhydrotrope solubilizers or couplers can be used at concentrations thatmaintain phase stability but do not result in unwanted compositionalinteraction.

Representative classes of hydrotrope solubilizers or coupling agentsinclude an anionic surfactant such as an alkyl sulfate, an alkyl oralkane sulfonate, a linear alkyl benzene or naphthalene sulfonate, asecondary alkane sulfonate, alkyl ether sulfate or sulfonate, an alkylphosphate or phosphonate, dialkyl sulfosuccinic acid ester, sugar esters(e.g., sorbitan esters) and a C₈₋₁₀ alkyl glucoside.

Preferred coupling agents for use in the present compositions andmethods include n-octane sulfonate and aromatic sulfonates such as analkyl aryl sulfonate (e.g., sodium xylene sulfonate or naphthalenesulfonate). Many hydrotrope solubilizers independently exhibit somedegree of antimicrobial activity at low pH. Such action adds to theefficacy of the invention but is not a primary criterion used inselecting an appropriate solubilizing agent. Since the presence of theperoxycarboxylic acid material in the protonated neutral state providesbeneficial biocidal or antimicrobial activity, the coupling agent shouldbe selected not for its independent antimicrobial activity but for itsability to provide effective single phase composition stability in thepresence of substantially insoluble peroxycarboxylic acid materials andthe more soluble compositions of the invention. Generally, any number ofsurfactants may be used consistent with the purpose of this constituent.

Anionic surfactants useful with the invention include alkylcarboxylates, linear alkylbenzene sulfonates, paraffin sulfonates andsecondary n-alkane sulfonates, sulfosuccinate esters and sulfated linearalcohols.

Zwitterionic or amphoteric surfactants useful with the invention includeβ-N-alkylaminopropionic acids, n-alkyl-β-iminodipropionic acids,imidazoline carboxylates, n-alky-Iletaines, amine oxides, sulfobetainesand sultaines.

Nonionic surfactants useful in the context of this invention aregenerally polyether (also known as polyalkylene oxide, polyoxyalkyleneor polyalkylene glycol) compounds. More particularly, the polyethercompounds are generally polyoxypropylene or polyoxyethylene glycolcompounds. Typically, the surfactants useful in the context of thisinvention are synthetic organic polyoxypropylene (PO)-polyoxyethylene(EO) block copolymers. These surfactants have a diblock polymerincluding an EO block and a PO block, a center block of polyoxypropyleneunits (PO), and having blocks of polyoxyethylene grated onto thepolyoxypropylene unit or a center block of EO with attached PO blocks.Further, this surfactant can have further blocks of eitherpolyoxyethylene or polyoxypropylene in the molecule. The averagemolecular weight of useful surfactants ranges from about 1000 to about40,000 and the weight percent content of ethylene oxide ranges fromabout 10-80% by weight.

Also useful in the context of this invention are surfactants includingalcohol alkoxylates having EO, PO and BO blocks. Straight chain primaryaliphatic alcohol alkoxylates can be particularly useful as sheetingagents. Such alkoxylates are also available from several sourcesincluding BASF Wyandotte where they are known as “Plurafac” surfactants.A particular group of alcohol alkoxylates found to be useful are thosehaving the general formula R-(EO)_(m)-(PO)_(n) wherein m is an integerof about 2-10 and n is an integer from about 2-20. R can be any suitableradical such as a straight chain alkyl group having from about 6-20carbon atoms.

Other useful nonionic surfactants include capped aliphatic alcoholalkoxylates. These end caps include but are not limited to methyl,ethyl, propyl, butyl, benzyl and chlorine. Useful alcohol alkoxylatedinclude ethylene diamine ethylene oxides, ethylene diamine propyleneoxides, mixtures thereof, and ethylene diamine EO-PO compounds,including those sold under the tradename Tetronic. Preferably, suchsurfactants have a molecular weight of about 400 to 10,000. Cappingimproves the compatibility between the nonionic and the oxidizershydrogen peroxide and peroxycarboxylic acid, when formulated into asingle composition. Other useful nonionic surfactants arealkylpolyglycosides.

Another useful nonionic surfactant is a fatty acid alkoxylate whereinthe surfactant includes a fatty acid moiety with an ester groupincluding a block of EO, a block of PO or a mixed block or hetericgroup. The molecular weights of such surfactants range from about 400 toabout 10,000, a preferred surfactant has an EO content of about 30 to 50wt-% and wherein the fatty acid moiety contains from about 8 to about 18carbon atoms.

Similarly, alkyl phenol alkoxylates have also been found useful in theinvention. Such surfactants can be made from an alkyl phenol moietyhaving an alkyl group with 4 to about 18 carbon atoms, can contain anethylene oxide block, a propylene oxide block or a mixed ethylene oxide,propylene oxide block or heteric polymer moiety. Preferably suchsurfactants have a molecular weight of about 400 to about 10,000 andhave from about 5 to about 20 units of ethylene oxide, propylene oxideor mixtures thereof.

The concentration of hydrotrope useful in the present inventiongenerally ranges from about 0.1 to about 20 wt-%, preferably from about0.5 to about 10 wt-%, most preferably from about 1 to about 4 wt-%.

Thickening or Gelling Agents

Thickeners useful in the present invention include those which do notleave contaminating residue on the surface of food product or foodproduct processing apparatus. That is, preferred thickeners or gellingagents do not include components incompatible with food or othersensitive products in contact areas.

Generally, thickeners which may be used in the present invention includenatural gums such as xanthan gum, guar gum, or other gums from plantmucilage; polysaccharide based thickeners, such as alginates, starches,and cellulosic polymers (e.g., carboxymethyl cellulose); polyacrylatesthickeners; and hydrocolloid thickeners, such as pectin. Generally, theconcentration of thickener employed in the present compositions ormethods will be dictated by the desired viscosity within the finalcomposition. However, as a general guideline, the viscosity of thickenerwithin the present composition ranges from about 0.1 wt-% to about 1.5wt-%, preferably from about 0.1 wt-% to about 1.0 wt-%, and mostpreferably from about 0.1 wt-% to about 0.5 wt-%.

Formulation

The compositions of or used in the methods of the invention can beformulated by combining the antimicrobially active materials (e.g.,aliphatic carboxylic mono- or di-esters, and hydrogen peroxide) withadjuvant or other components with the materials that form thereduced-odor composition. The compositions can also be formulated withpreformed peroxycarboxylic acids. The preferred compositions of theinvention can be made by mixing the aliphatic carboxylic mono- ordi-esters or mixture thereof with an optional hydrotrope solubilizer orcoupler, reacting the mixture with hydrogen peroxide and then adding thebalance of required ingredients to provide rinsing and antimicrobialaction.

A stable equilibrium mixture is produced containing the carboxylic acidor blend with hydrogen peroxide and allowing the mixture to stand for1-14 days at 15° C. or more. With this preparatory method, anequilibrium mixture will be formed containing an amount of hydrogenperoxide, unoxidized acid, oxidized or peroxycarboxylic acid andunmodified couplers, solubilizer, or stabilizers.

Use Compositions

The invention contemplates a concentrate composition which is diluted toa use solution prior to application to an object. Primarily for reasonsof economics, the concentrate would normally be marketed and an end userwould preferably dilute the concentrate with water or an aqueous diluentto a use solution.

The level of active components in the concentrate composition isdependent on the intended dilution factor and the desired activity ofthe peroxycarboxylic acid compound and the carboxylic acid. Generally, adilution of about 0.5 to about 20 fluid ounces to about 100 gallons ofwater is used for aqueous antimicrobial compositions. Higher usedilutions can be employed if elevated use temperature (greater than 25°C.) or extended exposure time (greater than 30 seconds) can be employed.In the typical use locus, the concentrate is diluted with a majorproportion of water using commonly available tap or service water mixingthe materials at a dilution ratio of about 3 to about 20 ounces ofconcentrate per 100 gallons of water.

Methods Employing the Reduced-Odor Peroxycarboxylic Acid Compositions

The present invention includes methods employing the reduced-odorperoxycarboxylic acid compositions. Typically, these methods employ theantimicrobial or bleaching activity of the peroxycarboxylic acid. Forexample, the invention includes a method for reducing a microbialpopulation, a method for reducing the population of a microorganism onskin, a method for treating a disease of skin, a method for reducing anodor, a method for bleaching. These methods can operate on an object,surface, in a body or stream of water or a gas, or the like, bycontacting the object, surface, body, or stream with a reduced-odorperoxycarboxylic acid composition of the invention. Contacting caninclude any of numerous methods for applying a composition, such asspraying the composition, immersing the object in the composition, foamor gel treating the object with the composition, or a combinationthereof.

The present reduced-odor compositions can be employed for reducing thepopulation of pathogenic microorganisms, such as pathogens of humans,animals, and the like. The reduced-odor compositions can exhibitactivity against pathogens including fungi, molds, bacteria, spores, andviruses, for example, parvovirus, coxsackie virus, herpes virus, S.aureus, E. coli, Streplococci, Legionella, mycobacteria, or the like.Such pathogens can cause a varieties of diseases and disorders,including athletes foot, hairy hoof wart disease, mastitis or othermammalian milking diseases, tuberculosis, and the like. The compositionsof the present invention can reduce the population of microorganisms onskin or other external or mucosal surfaces of an animal. In addition,the present compositions can kill pathogenic microorganisms that spreadthrough transfer by water, air, or a surface substrate. The compositionneed only be applied to the skin, other external or mucosal surfaces ofan animal water, air, or surface. A filter containing the compositioncan reduce the population of microorganisms in air and liquids.

A concentrate or use concentration of a reduced-odor peroxycarboxylicacid composition of the present invention can be applied to or broughtinto contact with an object by any conventional method or apparatus forapplying an antimicrobial or cleaning composition to an object. Forexample, the object can be wiped with, sprayed with, and/or immersed inthe reduced-odor composition, or a use composition made from thereduced-odor composition. Contacting can be manual or by machine. Foodprocessing surfaces, food products, food processing or transport waters,and the like can be treated with liquid, gel, aerosol, gas, wax, solid,or powdered reduced-odor compositions according to the invention, orsolutions containing these compositions.

Contacting a Food Product with the Reduced-Odor Peroxycarboxylic AcidCompositions

The present method and system provide for contacting a food product witha reduced-odor composition employing any method or apparatus suitablefor applying a reduced-odor composition. For example, the method andsystem of the invention can contact the food product with a spray of areduced-odor composition, by immersion in the reduced-odor composition,by foam or gel treating with the reduced-odor composition, or the like.Contact with a spray, a foam, a gel, or by immersion can be accomplishedby a variety of methods known to those of skill in the art for applyingantimicrobial agents to food. These same methods can also be adapted toapply the reduced-odor compositions of the invention to other objects.

The present methods require a certain minimal contact time of thecomposition with food product for occurrence of significantantimicrobial effect. The contact time can vary with concentration ofthe use composition, method of applying the use composition, temperatureof the use composition, amount of soil on the food product, number ofmicroorganisms on the food product, type of antimicrobial agent, or thelike. Preferably the exposure time is at least about 5 to about 15seconds.

A preferred method for washing food product employs a pressure sprayincluding the reduced-odor composition. During application of the spraysolution on the food product, the surface of the food product can bemoved with mechanical action, preferably agitated, rubbed, brushed, etc.Agitation can be by physical scrubbing of the food product, through theaction of the spray solution under pressure, through sonication, or byother methods. Agitation increases the efficacy of the spray solution inkilling micro-organisms, perhaps due to better exposure of the solutioninto the crevasses or small colonies containing the micro-organisms. Thespray solution, before application, can also be heated to a temperatureof about 15 to 20° C., preferably about 20 to 60° C. to increaseefficacy. The spray reduced-odor composition can be left on the foodproduct for a sufficient amount of time to suitably reduce thepopulation of microorganisms, and then rinsed, drained, or evaporatedoff the food product.

Application of the material by spray can be accomplished using a manualspray wand application, an automatic spray of food product moving alonga production line using multiple spray heads to ensure complete contact,or other spray apparatus. One preferred automatic spray applicationinvolves the use of a spray booth. The spray booth substantiallyconfines the sprayed composition to within the booth. The productionline moves the food product through the entryway into the spray booth inwhich the food product is sprayed on all its exterior surfaces withsprays within the booth. After a complete coverage of the material anddrainage of the material from the food product within the booth, thefood product can then exit the booth. The spray booth can include steamjets that can be used to apply the reduced-odor compositions of theinvention. These steam jets can be used in combination with coolingwater to ensure that the treatment reaching the food product surface isless than 65° C., preferably less than 60° C. The temperature of thespray on the food product is important to ensure that the food productis not substantially altered (cooked) by the temperature of the spray.The spray pattern can be virtually any useful spray pattern.

Immersing a food product in a liquid reduced-odor composition can beaccomplished by any of a variety of methods known to those of skill inthe art. For example, the food product can be placed into a tank or bathcontaining the reduced-odor composition. Alternatively, the food productcan be transported or processed in a flume of the reduced-odorcomposition. The washing solution is preferably agitated to increase theefficacy of the solution and the speed at which the solution reducesmicro-organisms accompanying the food product. Agitation can be obtainedby conventional methods, including ultrasonics, aeration by bubbling airthrough the solution, by mechanical methods, such as strainers, paddles,brushes, pump driven liquid jets, or by combinations of these methods.The washing solution can be heated to increase the efficacy of thesolution in killing micro-organisms. After the food product has beenimmersed for a time sufficient for the desired antimicrobial effect, thefood product can be removed from the bath or flume and the reduced-odorcomposition can be rinsed, drained, or evaporated off the food product.

In another alternative embodiment of the present invention, the foodproduct can be treated with a foaming version of the composition. Thefoam can be prepared by mixing foaming surfactants with the washingsolution at time of use. The foaming surfactants can be nonionic,anionic or cationic in nature. Examples of useful surfactant typesinclude, but are not limited to the following: alcohol ethoxylates,alcohol ethoxylate carboxylate, amine oxides, alkyl sulfates, alkylether sulfate, sulfonates, quaternary ammonium compounds, alkylsarcosines, betaines and alkyl amides. The foaming surfactant istypically mixed at time of use with the washing solution. Use solutionlevels of the foaming agents is from about 50 ppm to about 2.0 wt-%. Attime of use, compressed air can be injected into the mixture, thenapplied to the food product surface through a foam application devicesuch as a tank foamer or an aspirated wall mounted foamer.

In another alternative embodiment of the present invention, the foodproduct can be treated with a thickened or gelled version of thecomposition. In the thickened or gelled state the washing solutionremains in contact with the food product surface for longer periods oftime, thus increasing the antimicrobial efficacy. The thickened orgelled solution will also adhere to vertical surfaces. The compositionor the washing solution can be thickened or gelled using existingtechnologies such as: xanthan gum, polymeric thickeners, cellulosethickeners, or the like. Rod micelle forming systems such as amineoxides and anionic counter ions could also be used. The thickeners orgel forming agents can be used either in the concentrated product ormixing with the washing solution, at time of use. Typical use levels ofthickeners or gel agents range from about 100 ppm to about 10 wt-%.

EXAMPLES Example 1 Embodiments of Reduced Odor Peroxycarboxylic AcidCompositions

Octyldimethylamine oxide was added to a peracid composition containing15% peroxyacetic acid, 10% hydrogen peroxide, and about 40-45% aceticacid. The octyldimethylamine oxide was added at different levels,corresponding to differing molar ratios of peroxyacetic acid (POAA) toacetic acid (AA) to octyldimethylamine oxide (AO-8). The mixture wasthen compared for remaining odor. As the table below illustrates, amolar ratio 1 or more AO-8 to 1 POAA exhibited a significant reductionin odor. It was surprising that this reduction occurred even at pH toolow for ion pair formation between the AO-8 and POAA, i.e. substantiallybelow the 8.2 pKa of POAA.

Odor reduction was also observed for lauryldimethylamine oxide, at amole ratio of 1 or greater.

moles mixture results POAA AA AO-8 pH odor 1 3 0 1.8 ouch! 1 3 1 3.3vinegar 1 3 2 3.7 slight vinegar 1 3 3 4.8 amine oxide 1 3 4 4.8 amineoxide 1 3 5 5.2 amine oxide 1 3 1 2.0* vinegar 0 0 1 7.7 amine oxide *pHadjusted with conc. sulfuric acid

It should be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the content clearly dictates otherwise. Thus, for example,reference to a composition containing “a compound” includes a mixture oftwo or more compounds. It should also be noted that the term “or” isgenerally employed in its sense including “and/or” unless the contentclearly dictates otherwise.

All publications and patent applications in this specification areindicative of the level of ordinary skill in the art to which thisinvention pertains.

The invention has been described with reference to various specific andpreferred embodiments and techniques. However, it should be understoodthat many variations and modifications may be made while remainingwithin the spirit and scope of the invention.

1. A reduced-odor peroxycarboxylic acid composition comprising: at leastone peroxycarboxylic acid; and amine oxide of the formula (R₁R₂R₃)NO,wherein R₁, R₂, and R₃ are alkyl groups, the R₁ alkyl group having 4 to18 carbon atoms, and the R₂ and R₃ alkyl groups having 1 to 2 carbonatoms; the amine oxide being effective for reducing the odor of theperoxycarboxylic acid; the composition comprising 2 to 5 moles of amineoxide per mole of peroxycarboxylic acid.
 2. The composition of claim 1,wherein the amine oxide consists of octyldimethylamine oxide,lauryldimethylamine oxide, or a mixture thereof.
 3. The composition ofclaim 1, wherein the R₁ alkyl group has 12 carbon atoms.
 4. Thecomposition of claim 1, wherein the R₁ alkyl group has 6 to 8 carbonatoms.
 5. The composition of claim 1, wherein the mole ratio of amineoxide to peroxycarboxylic acid is greater than
 3. 6. The composition ofclaim 1, wherein the at least one peroxycarboxylic acid consists ofperoxyacetic acid and the composition further comprises acetic acid. 7.The composition of claim 1, wherein the at least one peroxycarboxylicacid consists of peroxyformic acid, peroxyacetic acid, peroxypropionicacid, peroxybutanoic acid, peroxypentanoic acid, or mixture thereof. 8.A reduced-odor peroxycarboxylic acid composition comprising:peroxyacetic acid; and octyl dimethyl amine oxide or octyl diethyl amineoxide; the amine oxide being effective for reducing the odor of theperoxycarboxylic acid; the composition comprising 2 to 5 moles of amineoxide per mole of peroxycarboxylic acid.
 9. The composition of claim 1,additionally comprising: hydrogen peroxide.
 10. The composition of claim9, additionally comprising: at least one carboxylic acid.
 11. Thecomposition of claim 1, wherein at least one peroxycarboxylic acidcomprises one or more C₂-C₄ peroxycarboxylic acids, one or more C₈-C₁₂peroxycarboxylic acids, or one or more alkyl ester peroxycarboxylicacid.
 12. The composition of claim 8, additionally comprisingperoxyoctanoic acid or peroxydecanoic acid.